1. Field of the Invention
In general, the present invention relates to the production of expanded mesh sheets. In particular, the present invention relates to the production of expanded mesh sheets which are utilized to produce battery grids.
2. Prior Art
The prior art has long recognized the advantages to be gained by utilizing expanded mesh material in the formation of battery grids. There have been a number of efforts to produce a satisfactory grid and these efforts have produced a number of different approaches. One of the more recent approaches to the problems encountered with battery grids suggests expanding the slit and preformed portion of a metal strip by drawing opposite longitudinal edges of the strip apart so that the curved segments are substantially straightened while the nodes remain substantially in the plane of the strip to form the mesh sheet. Experience gained in efforts to practice this expansion method, as disclosed in U.S. Pat. Nos. 4,291,443 and 4,315,356, has shown that the disclosed method and apparatus does not produce satisfactory grids in those applications where the final pattern of grid interstices is not uniform. Accordingly, efforts were undertaken to develop an apparatus which would produce commercially acceptable grids having varied interstices.
To the extent that U.S. Pat. Nos. 4,291,443 and 4,315,356 disclose an apparatus for simultaneously slitting and preforming a portion of a metal strip prior to expansion, that apparatus is suitable for simultaneous use with the present invention and the description thereof is incorporated herein as if fully set forth.
As used hereinafter, the apparatus for slitting and preforming metal sheet will be generally referred to as a slitting head.